Screw cap for a container

ABSTRACT

The invention provides a screw cap for a container wherein the cap has inner and outer sleeves, with a sealing member within, integral and transverse to the inner sleeve. The inner sleeve and sealing member are of hard plastics material, but the sealing member is thin enough to be sealingly resilient. A chamber between the sealing member, and a closed end of the outer sleeve prevents diffusion of aroma through the cap from the container.

United States Patent Ritzenhoff [54] SCREW CAP FOR A CONTAINER [72]Inventor: Hermann Ritzenhoff, Marburg an der Lahn, Germany [73]Assignee: Gebruder Seidel KG,

burg/Lahn, Germany [22] Filed: July 29, 1970 [21] Appl. N0.: 59,254

Mar-

[30] Foreign Application Priority Data Aug. 4, 1969 Germany ..P 19 39553.0

[52] US. Cl ..2l5/43 A, 215/40, 220/39 [51] Int. Cl. ..B65d 41/04 [58]Field of Search ..215/43 R, 43 A, 40; 220/39 [56] References CitedUNITED STATES PATENTS 3,199,704 8/1965 Davidson ..2 15/43 A 1 Aug. 22,1972 Flynn ..2l5/43 A Metzendorf et al ..2l5/43 A PrimaryExaminer-George T. Hall Att0rney-George F. Dvorak, Stephen T. Skrydlakand Marden S. Gordon ABSTRACT 8 Clains, Drawing [figures SCREW CAP FOR ACONTAINER The invention relates to a screw cap for a container. Theinvention particularly relates to a screw cap made preferably fromthermoplastics material and intended for cosmetics containers and thelike.

Various two-part screw caps are known having outer and inner sleevesmade from different materials, for example glass-plastics ormetal-plastics.

Such decorative screw caps can have inner and outer sleeves made fromplastics, the outer sleeve being of a hard plastics material and theinner sleeve (or at least a sealing disc) being of soft plasticsmaterial.

Decorative screw caps arefrequently relatively high, i.e., they have abody which is longer than is in fact necessary, so that a cavity isformed within the outer sleeve which is not used. They normally have ascrewthread on the lower, open ends, and a sealing or packing disc or aninner sleeve the bottom of which serves as a sealing or packing disc.

Known screw caps are, for reasons of strength, generally made from aplastics material of high hardness whereas the sealing disc is made froma soft plastics material so as to be flexible. Because the screwthreadis at the open end, it is not possible to make the internal diameter ofthe upper parts greater than the smallest diameter of the screwthread,so that the upper wall thickness is greater than it need be, and excessmaterial is used. Also, because of the variations in wall thickness,injection moulding and curing can be difficult, and accuracy isdifficultto attain while manufacture is relatively lengthy in time.There is also a tendency for the packing or sealing discs to drop out,and this can be difficult to position.

The sealing disc must also be firmly positioned and quite strong so thatit firmly engages the opening in the container. It must therefore bethick, but also resilient to give a good seal. If the screw cap is usedfor cosmetic containers, the sealing disc must be thick enough to reducepermeation of the aroma therethrough to acceptable limits.

It is an object of the present invention to provide an improved screwcap for a container.

According to the invention, there is provided a screw cap for acontainer, said cap including an outer sleeve with a closed end,containing an inner sleeve carrying a screw thread and having asubstantially transverse sealing member integral therewith, wherein achamber is defined between the sealing face, closed end and sleeves, andthe inner sleeve and sealing face are of hard plastics material, thesealing member being sufficiently thin to be sealingly resilient.

The screw cap may include a hollow conical portion at the end of theinner sleeve adjacent the closed end of the outer sleeve. A support forthe sealing member can be provided in the chamber. The support maycomprise a pin fixed to either the sealing member or the closed end ofthe outer sleeve.

The screw cap may have abutrnents between the end of the inner sleeveand the closed end of the outer sleeve. The abutrnents may be in theform of annular ribs, and further ribs can be provided extendingtherefrom, to engage, for instance, in notches in the inner end of theinner sleeve.

The inner sleeve can be held in the outer sleeve by means of, forinstance, annular projection on one sleeve engaging in correspondingrecesses in the other sleeve.

An advantage of the present invention is that two identical or similarplastics materials are used for the outer and inner sleeves, withsatisfactory sealing being assured by the thin sealing member. Althougharoma may diffuse through this thin sealing member, it only diffusesinto the chamber, and does not go further. The chamber acts as a bufferfor the aroma. The sealing member is supported by the inner sleeve.

With screw caps according to the invention, the wall thickness,particularly of the outer sleeve, is substantially uniform, so thatinjection moulding of thermoplastics materials is extremely easy, andcuring of thermosetting materials in the required shape is also easy.Manufacturing times are short, and material consumption small, whilegood accuracy can be obtained.

The screw cap may also have a decorative ring abutting the open end ofthe outer sleeve and preferably supported on the inner sleeve. The ringmay be positioned on a projecting rim on the inner sleeve, the externaledges of the rim being rounded to facilitate the application of thering. This arrangement is made possible by the two-part moulding of thescrew cap of the invention.

In order that the invention may be more clearly understood, thefollowing description is given, merely by way of example, with referenceto the accompanying drawings, in which:

FIGS. 1 4 show known screw caps,

FIG. 5 shows a section through one form of screw cap according to theinvention, and

FIG. 6 shows a detail of FIG. 5, drawn to a larger scale.

A known screw cap, la, which is made in one piece, is shown in FIG. 1.It has a screwthread 2a at its open end, and narrows above this toprovide a face 3a against which bears a sealing disc 4a. A decorativering 5a, made from metal, is titted in a recess near the open end. Thecap is made from plastics material of high hardness, with the sealingdisc 4a of soft plastics to provide a good seal.

FIG. 2 shows a screw cap having a cup 4b the open end of which contactsthe bottom of the cap 1b and the head of which comprises a sealing face.Less material is required for the cap in this case, but more material isrequired for the cap 4b than for the sealing disc 4a used in the screwcap of FIG. 1.

FIG. 3 shows a screw cap with an external sleeve 6 and an inner sleeve 7made from a soft thermoplastics material. In this case, the outer sleevesupports the inner sleeve, and contacts it over a wide area. The innersleeve is relatively thick which is undesirable.

The screw cap of FIG. 4 has a separate sealing insert 10 an inner sleeve8 and an outer sleeve 9 which, for decorative purposes, may be designedto have any desired height.

The screw cap according to the invention which is shown in FIG. 5consists of an outer sleeve 11 and an inner sleeve 12. The inner sleeve12 has an internal screwthread located just below a transverse sealingmember 21 integral with the inner sleeve. The inner sleeve also carriesa decorative ring 13. The inner sleeve is made of a relatively hardthermoplastics material, such as for example polypropylene, and theintegral sealing member 21 is of the same material, but is sufficientlythin to be suitably resilient. Material from within the container to besealed may diffuse through the thin sealing member into the chamber 22defined by the sealing member, the closed end of the outer sleeve andthe inner sleeve. This chamber acts as a buffer, preventing the aromadissipating further. It need only be charged with aroma once, as the capis not normally removed form the container long enough to allowdiffusion out of the chamber again. Thus an aromatic seal is achievedeven with the thin sealing member.

Assembly of the screw cap is facilitated by a conical portion 14 at theinner end of the inner sleeve.

The sealing member is supported as shown by pin 15 attached thereto. Itcould equally be attached to the end of the outer sleeve, or a planarsupport could be used.

When the inner sleeve is pressed into the outer sleeve on assembly, itis stopped by a projecting rim 16 at its lower end, and, or by arrestingribs 17 arranged internally in the outer sleeve 11.

A latching effect between the inner and outer sleeve is achieved byrelatively deep ribs 18 within the outer sleeve 11 which engage incorresponding recesses formed in the conically tapered end 14 of theinner sleeve.

The latching effect between the inner and outer sleeves may be improvedby providing interengaging ribs and grooves on the contacting surfaces.The rims and grooves are preferably tapered, and of sawtooth shape.

A projecting edge 16 on the inner sleeve 12 has two externallypositioned edges 19 and 20. The rounding of the edge 19 facilitatespushing-on of the decorative ring 13 while the rounding of the edge 20ensures that the rim stays in place. This double rounded edged shapecould previously only be obtained with a separate manufacturing step,but can be made in this case by having a two-part mould for the innersleeve, with a dividing line at the highest part of the rim 16.

We claim:

1. A two-piece decorative screw cap for a cosmetic container and thelike, said cap comprising in combinat1on:

a an elongate outer sleeve;

b an end wall to said outer sleeve, and an end to said outer sleeveremote from said end wall;

c an inner sleeve located in said outer sleeve and having one endadjacent said end wall, and another end remote from said one end;

d an axis and an inner surface to said inner sleeve;

e screw thread means on at least a part of said inner surface;

f a sealing member located within and integral with said inner sleeve,and being substantially transverse to the axis of said inner sleeve;said sealing member, end wall and sleeves defining a space, and saidinner sleeve and said sealing member being of a relatively hardthermoplastics material, said sealing member being sufficiently thin tobe sealingly resilient and to permit diffusion into said space.

2. A screw cap as claimed in claim 1, wherein said lf' li ilfiti ciifi afifi%3= 1%1 ififi?wmprising a support for said sealing member located insaid space.

4. A screw cap as claimed in claim 3, wherein said support comprises apin substantially aligned with said axis of said inner sleeve.

5. A screw cap as claimed in claim 1, further comprising abutrnent ribsin said outer sleeve contacted by said end of said inner sleeve which isadjacent said end wall.

6. A screw cap as claimed in claim 5, further comprising furtherabutment ribs, means defining notches in said end of said inner sleevewhich is adjacent said end wall, said further ribs being engaged in saidnotches.

7. A screw cap for a container, said cap comprising in combination:

a an outer sleeve;

b an end wall to said outer sleeve, and and end to said outer sleeveremote from said end wall;

0 an inner sleeve located in said outer sleeve and having one endadjacent said end wall, and another end remote from said one end;

d an axis and an inner surface to said inner sleeve;

e screw thread means on at least a part of said inner surface;

f a sealing member located within and integral with said inner sleeve,and being substantially transverse to the axis of said inner sleeve;said sealing member, end wall and sleeves defining a space, and saidinner sleeve and said sealing member being of a hard plastics material,said member being sufficiently thin to be sealingly resilient and adecorative ring supported on said inner sleeve and abutting said outersleeve at said end thereof remote from said end wall.

8. A screw cap as claimed in claim 7, further comprising an outwardlyprojecting rim having rounded edges on said inner sleeve at said anotherend thereof, said decorative ring being disposed on said rim.

1. A two-piece decorative screw cap for a cosmetic container and the like, said cap comprising in combination: a. an elongate outer sleeve; b. an end wall to said outer sleeve, and an end to said outer sleeve remote from said end wall; c. an inner sleeve located in said outer sleeve and having one end adjacent said end wall, and another end remote from said one end; d. an axis and an inner surface to said inner sleeve; e. screw thread means on at least a part of said inner surface; f. a sealing member located within and integral with said inner sleeve, and being substantially transverse to the axis of said inner sleeve; said sealing member, end wall and sleeves defining a space, and said inner sleeve and said sealing member being of a relatively hard thermoplastics material, said sealing member being sufficiently thin to be sealingly resilient and to permit diffusion into said space.
 2. A screw cap as claimed in claim 1, wherein said inner sleeve and sealing face are of polypropylene.
 3. A screw cap as claimed in claim 1, further comprising a support for said sealing member located in said space.
 4. A screw cap as claimed in claim 3, wherein said support comprises a pin substantially aligned with said axis of said inner sleeve.
 5. A screw cap as claimed in claim 1, further comprising abutment ribs in said outer sleeve contacted by said end of said inner sleeve which is adjacent said end wall.
 6. A screw cap as claimed in claim 5, further comprising further abutment ribs, means defining notches in said end of said inner sleeve which is adjacent said end wall, said further ribs being engaged in said notches.
 7. A screw cap for a container, said cap comprising in combination: a. an outer sleeve; b. an end wall to said outer sleeve, and an end to said outer sleeve remote from said end wall; c. an inner sleeve located in said outer sleeve and having one end adjacent said end wall, and another end remote from said one end; d. an axis and an inner surface to said inner sleeve; e. screw thread means on at least a part of said inner surface; f. a sealing member located within and integral with said inner sleeve, and being substantially transverse to the axis of said inner sleeve; said sealing member, end wall and sleeves defining a space, and said inner sleeve and said sealing member being of a hard plaStics material, said member being sufficiently thin to be sealingly resilient and a decorative ring supported on said inner sleeve and abutting said outer sleeve at said end thereof remote from said end wall.
 8. A screw cap as claimed in claim 7, further comprising an outwardly projecting rim having rounded edges on said inner sleeve at said another end thereof, said decorative ring being disposed on said rim. 